In forming a power distribution system it is necessary to provide means for a hot line carrying power to the required load and a return line to the power source. In a typical power distribution system for an integrated circuit logic system as many as ten interconnections may be required. There are connections between power supply and bus bar, bus bar and a mother board, a mother board and the daughter board, and connections between the daughter board and socket in which chips are usually mounted and a connection between the socket and an actual integrated circuit. Thus there are five points of interconnection in the line going from the hot terminal to the load and another five points of interconnection complete the return line of the circuit. In many integrated circuit systems there can be no more than 250 millivolts of drop in the voltage at each load. Some logic systems furthermore require multiple voltage power distribution systems. These systems therefore require electrical connectors or contacts that will minimize voltage drops as the load is placed on the system.
The speed at which the systems are operated is continually being increased as technology advances. To accommodate the ever quickening rate of change in the current draw, power distribution systems were generally provided with capacitors mounted on the various boards to store current that would be readily available as the demands from the load change. This lumped element method presents problems in that there is insufficient space available to accommodate larger capacitors required for higher speed logic families or higher rates of change in current demand.
Power distribution systems are often designed to use a laminated bus-bar wherein the hot and return conductors are placed in close proximity separated by a thin insulative layer. One problem associated with laminated bus bars, however, is the inability to use standard two sided receptacle contacts to interconnect the laminated bus bar with another or to terminate to the laminated bus bar since a standard contact will electrically short the outer most conductive layers of the bus bar. Typically interconnections to laminated bus bars are made by providing the bus bar layers with tabs that extend outwardly from the various layers to which a wire or contact may be bolted to one voltage or layer. Since the wide bus bars are good conductors of heat as well as electricity, it is extremely difficult to achieve effective connections to the bus bar by soldering techniques. It is desirable to have a separately means for connecting to the laminated bus bar system that retains the "plugability" of the system.
Terminals such as those disclosed in U.S. Pat. Nos. 4,845,589 and 4,684,191 are receptacle terminals for providing severable interface for power interconnection to single layer bus bars. The terminals have opposing spring arms which together act as a flared receptacle to receive a bus bar therebetween. The bus bar engages contact sections of the spring arms and deflects the stiff spring arms outwardly thereby generating a sufficient contact normal force between the terminal and the bus bar. While the terminals described above are suitable for connecting to bus bars, the bus bars are ones that comprise a single unit carrying a single voltage. These terminals are unsuitable for use with laminated bus bars since they would provide an electrical connection or short between the outer conductive layers of the laminated bus bar.
U.S. Pat. No. 4,878,862 discloses an electrical connector for mating two blade-shaped members, each having opposed first and second sides. The connector comprises first and second terminal elements having body sections secured together with insulating means therebetween. Each first and second terminal element has a first and second arrays of spaced cantilevered spring contact arms extending outwardly from respective leading and trailing edges of the body section. The corresponding spring contact arms of the arrays of the terminal elements are interlaced proximate the leading and trailing edges, the spring contact arms of one terminal element extending into the spacing between contact arms of the other terminal element. The spring contact arms of the arrays define first and second blade-receiving receptacles. The free ends of the contact arms of the first and second arrays of the first terminal element are disposed along the second side of the first and second blade-receiving receptacles respectively and are adapted to be deflected outwardly by corresponding second sides of respective first and second mating blade-shaped members. The free ends of the spring contact arms of the first and second arrays of the second terminal element are disposed along the first side of the first and second blade-receiving receptacles respectively and are adapted to be deflected outwardly by corresponding first sides of respective first and second mating blade-shaped members. Since the respective contact arms of the terminal elements must pass through spaces between the contact arms of the other terminal element, the number of compliant spring arms and the proximity of the adjacent arms that can be accommodated in a given space is limited.